Synthesis, Characterisation, and Electrochemical Impedance Spectroscopy Study of Green and Sustainable Polyurethane Acrylate from Jatropha Oil Using a Three Step Process

Abstract

Bio-based polymer is a promising candidate to substitute conventional petroleum-derived polymer as it is sustainably produced from renewable resources, which helps reduce the production process’ carbon footprint. It also helps reduces humankind’s dependability on fossil fuel-based feedstock. In this work, a sustainable jatropha oil-based polyurethane acrylate (PUA) was successfully prepared and synthesised using a 3-steps process; epoxidation (formation of an epoxy group), hydroxylation (addition of–OH group to opened ring), and acrylation (addition of acrylate group into polyol). The yellowish PUA prepared has a gel consistency, which is sticky and slightly runny. The PUA was characterised by using wet chemical tests such as oxirane oxygen content (OOC), acid value (AV), hydroxyl number (OHV) and iodine value. OOC value for the PUA synthesised was 4.23 % at the 5 hr reaction time. At the same time, the Epoxidised jatropha oil (EJO) used to prepare polyol records a hydroxyl number of hydroxyl 185.81 mg KOH/g and an acid value of 1.06. The polyol prepared was mixed with 2, 4-toluene-diisocyanate (TDI) and Hydroetyhlmethacrylate (HEMA) to produce PUA. The PUA was characterised by thermogravimetry analysis (TGA) and electrochemical impedance spectroscopy (EIS). TGA analysis shows that the polymer is stable up to 373 K, whereas the EIS analysis records an ionic conductivity of (5.60±0.03) × 10-6 S cm-1. This polymer’s great thermal stability properties make it suitable for outdoor application where high temperature due to sun exposure is common. Furthermore, PUA prepared gel-like properties to make it a suitable candidate for preparing a gel polymer electrolyte.